I did not mention on my observation on the 9th and 10th of July I finished my night watching Io come out from behind of Jupiter on the side. Wonderful watching this though I wish the transparency had been better.
This made me do some research on Jupiter. On the night of September 2nd and 3rd, of this year the Galilean moons will not be visible for around 2 hours. This last occurred on May 21st,
2008. According to this article from MSNBC:
In case your wondering, Kelly Beaty in Sky and Telescope discussed the same event that happen in 2008 for Europe, Africa and very briefly for the eastern coast of North America. As Jean Meeus points out this event occurs about 25 or so times a century but the key is how many times it happens where we live so we can see it. I figure I have this event in September and then maybe one or two more times in my life for t his to be seen where I live. Here's some further info:
According to Jean Meeus
Kelly Beaty's article from last year:
Sky&Telescope has a nice Jupiter Almanac as a PDF called Phenomena of Jupiter’s Moons that shows the event in their September 2009. Add six hours to the times listed as they are
universal times. That link is found here:
Another site I found interesting is this one at mjpowell astro site.
It has some interesting information regarding Jupiter and objects to view with it.
One is the position of Neptune with Jupiter this year located here
I'm sure most of you know that Jupiter and Neptune are undergoing a triple
conjunction this year, first time since 1971.
"The first of the 2009 conjunctions took place on May 25th 2009, when
Jupiter (at magnitude -2.4) was moving direct (or prograde, i.e. West
to East) against the star background and Neptune (at magnitude +7.9)
was approaching its Eastern stationary point. The two planets were
separated vertically by 25' (25 arcminutes, or just under half a
degree) at this point, and were visible in the morning sky before
sunrise. The second conjunction takes place on July 13th 2009, when
both Jupiter (mag. -2.7) and Neptune (mag. +7.8) are retrograding
(moving East to West) against the star background; the planets are
separated by 36' (0°.6) at this point, and are visible from the late
evening onwards. Jupiter then reaches opposition to the Sun on August
14th (having brightened to mag. -2.8), followed only three days later
by Neptune (at mag. +7.8). Finally, the planets are again in
conjunction on December 20th 2009, when both Jupiter (-2.2) and
Neptune (+7.9) have resumed direct motion, the pair then being
separated by 33' (0°.55); this conjunction is visible in the evening
sky, shortly after sunset."
So Monday is a time when you may want to take a look at Jupiter and
Neptune with the second of three conjunctions and then again on
December 20th, 2009 per the site.
If you follow this link from the same site from the same website you can learn that from 2010 to 2011 Jupiter and Uranus will have a triple conjunction and this will not happen again until 2037 to 2038 (I'll be in my early 70's if I live that long I hope) and this hasn't happen since 1983. So for me I am putting this down in my calendar since I don't want to miss them. If you don't want to go and scroll halfway down to see the info I'll quote part of it here:
"The first of the 2010-11 conjunctions takes place on June 6th, 2010, when both Jupiter (at magnitude -2.3) and Uranus (at magnitude +5.9) are moving direct (or prograde, i.e. West to East) against the star background. The two planets are separated vertically by 29' (29 arcminutes, or just under half a degree) at this point, and are visible in the early morning sky. The second conjunction takes place on September 22nd, 2010, when both Jupiter (mag. -2.9) and Uranus (mag. -+5.7) are retrograding (moving East to West) against the star background; the planets are separated by 53' (0.88 degrees) at this point, and are visible throughout the night. This is also the day on which both planets reach opposition to the Sun, there being just 5 hours separating the two planet's opposition times (this is known as paired opposition). Finally, the planets are again in conjunction on January 2nd, 2011, when both Jupiter (-2.3) and Uranus (+5.9) have resumed direct motion, the pair then being separated by 34" (0.56 degree); this conjunction is visible in the evening sky shortly after sunset."
So remember to go out on Monday the 13th of July (tomorrow) and see the 2nd conjunction of Neptune and Jupiter for this year. Also, the links above on Jupiter and Neptune have a finder chart for finding Neptune from Jupiter from now until December so if you haven't seen Neptune, now is a good time to do so. Finally, I hope you look forward to viewing the four Galilean moons disappear from around Jupiter. Clear skies to each of you.